On the rare occasions they appear on grocery store shelves in North America, lychees will catch the eye with their rosy-hued rinds. Dig into the peel with your fingernail, and you'll find a mildly sweet, succulent flesh that's delicious on its own, but can be paired with a variety of other foods from sweet to savory. Fat-, cholesterol- and sodium-free, and a rich source of vitamin C, this is a food to stock up on. But don't overdo it; although lychees are healthy, eating too many can cause weight gain and other problems.
Any time your calorie intake exceeds your calorie expenditure, you're going to gain weight, although it may not be noticeable. If you do this for an extended period of time, you could gain quite a bit of weight. Lychees are fairly low in calories with 125 per 1-cup serving; however, if you're eating an excessive amount, say, 3 cups of the fruit in a day, you could be eating an extra 375 calories just from the fruit. If you're eating this amount every day in addition to your regular diet, you could gain about three-quarters of a pound every week, since 3,500 calories equals 1 pound of fat.
High in Carbs
Lychees are high in carbohydrates, especially sugar. A 1-cup serving of lychees has almost 30 grams of sugar. For comparison, apples have 13 grams of sugar per cup, apricots have 9 and blueberries have 7 grams per 1-cup serving. The sugars in fruit aren't anything to worry about if you eat fruit in moderation; however, if you eat excessive amounts of lychees, you could be getting too much sugar. Although there are no limits set on how much sugar you should have from natural sources, the Institute of Medicine recommends that adults should get no more than 65 percent of their calories from carbohydrates. Since lychees contain no protein and very little fat, getting a significant portion of your calories from the fruit may mean you're eating too high a percentage of carbs.
Missing Out on Other Important Nutrients
If you eat a lot of lychees, you might not have room for other important foods in your diet, such as lean protein, dairy, whole-grains and vegetables and other fruits, which all provide important nutrients you need to stay healthy. For example, lychees contain no protein, which you need for muscle growth and maintenance. They're also low in calcium, which you need to for strong bones and teeth. Lychees also supply very few fatty acids, which support heart health. The USDA recommends women eat 1 1/2 to 2 cups of fruits each day and men eat 2 cups per day.
Depending on where you live, you might not have access to fresh lychees. Canned lychees often contain added sugar, which in excess can be detrimental to your waistline and your health. A serving of canned lychees contains 27 grams of sugar, but not all of that is naturally occurring sugar. If you're eating too many canned lychees you could be surpassing the limit for added sugars recommended by the American Heart Association, which is 100 calories for women and 150 calories for men.